Calendar of Physics Talks Vienna

New Particle Searches at Belle

Speaker:

Jolanta Brodzicka (Institute of Nuclear Physics PAN, Krakow)

Abstract:

The recent discovery of several charmonium-like resonances indicates a renaissance of the $c\bar{c}$ spectroscopy. Many of these so called $XYZ$ states do not fit the conventional $c\bar{c}$ spectrum which is described, so far successfully, by the quark models. This suggests that some of them might be exotic. Majority of these observations come from the Belle experiment and have been enabled by the large data sample provided by the KEKB factory.
In this talk the recent experimental evidences of the $XYZ$ states will be presented along with discussion on future measurements which can shed light on the nature of these particles.

Date:

Tue, 12.04.2011

Time:

09:30

Duration:

60 min

Location:

SMI, Seminar room, Boltzmanngasse 3, 1090 Wien, Room 2.08

Contact:

Roland Gsell

Predicting electron transfer rates (with computer simulations)

Speaker:

Harald Oberhofer (TU München)

Abstract:

We show the feasibility of using computer simulations to calculate electron exchange reaction rates in extended systems from scratch. We achieve this by determining the dependence of all parameters occurring in the Marcus theory rate expression on the distance $r$ of Donor and Acceptor. Using both,

Crystalline films of conjugated organic semiconductors offer attractive potential for optoelectronic and electronic applications on flexible substrates. Due to the complexity and anisotropy of the molecular building blocks, novel growth mechanisms and rich self-organization phenomena can occur as is demonstrated for the growth of the rod-like oligophenylene molecule parasexiphenyl (6P). On clean mica(001), the self-organization of 6P crystallites into one-dimensional chains is observed by atomic-force microscopy (AFM) where the 6P molecules lie almost flat on the surface[1]. On an ion bombarded, amorphous mica surface, the formation of terraced mounds composed by almost upright standing molecules is observed. Quantitative analysis of the mound morphology together with transition state theory calculations reveals the existence of molecule bending during step edge crossing and level dependent Ehrlich Schwoebel barriers [2]. For the same system, the size of the critical nucleus has been determined from island size and capture zone distribution [3]. When growing 6P on Ir(111) supported graphene sheets, layer by layer growth up to at least four layers could be achieved, as has been recorded with low-energy electron microscopy [4].
[1] C. Teichert, et al., Appl. Phys. A 82 (2006) 665.
[2] G. Hlawacek, et al., Science 321 (2008) 108.
[3] T. Potocar, et al., Phys. Rev. B 83 (2011) 075423.
[4] G. Hlawacek, Nano Lett. 11 (2011) 333.